zoo lab 6 (phylum annelida w/ earthworm dissection)

what does “annelida” mean?

little rings

what types of habitats do annelids live in? (3)

marine, freshwater, moist terrestrial

there are more than ____ annelid species

15,000

most annelids are ___-living

free

some annelids are ___parasites

ecto

what type of symmetry do annelids have?

bilateral

what is the most significant feature of annelids?

segmentation

segmentation description

repeating units that contain their own sets of parts

what is an advantage of segmentation?

allows for specialization

what type of coelomates are annelids?

coelomates

every segment includes part of the…

coelom

what internal structure usually separates annelid segments?

septum

this type of annelid does not have septa (common name)

leech

annelid coeloms are filled with…

hydrostatic fluid

function of coelom with hydrostatic fluid

provides rigidity for muscle to contract against

2 types of muscle that surround coelom

circular, longitudinal

circular and longitudinal muscles work _____ each other

against

“direction” of circular muscles

go around

“direction” of longitudinal muscles

go lengthwise

what happens to annelid segments when circular muscles contract?

they get long and thin

what happens to annelid segments when longitudinal muscles contract?

they get short and wide

setae description and general function

little hairs, help locomotion

what do setae specifically do for earthworms?

anchor and help move through dirt

key part of annelid excretory system

metanephridia

annelids have a _____ gut and ______ digestive tract

central, complete

what is a unique feature of annelid guts?

typhlosole

typhlosole description and function

folding of gut, increases surface area for digestion

the septa prevent ______ fluid from moving between segments

hydrostatic

annelids have a ____ circulatory system

closed

key parts of annelids’ simple nervous system

2 dorsal cerebral ganglia, 1 ventral nerve cord

some annelids have ___, but most breathe through their ___

gills, skin

most annelids are ___ecious

mono

what is the only way annelids can fertilize eggs?

cross-fertilization

description of cross-fertilization

sperm swap

clitellum function

produces foamy cocoon for sperm travel and fertilized eggs

sandworm classification (phylum, class, genus)

phylum annelida, class errantia, genus nereis

4 distinguishing features of nereis

parapodia, eyes, jaws, tentacles

function of tentacles and palps in nereis

sensory organs

organisms in class errantia have a more well-developed ___ region

head

parapodia functions (2)

respiration, locomotion

what extends out from parapodia?

setae

most annelids have two main blood vessels- one is ____, the other is ____ (location-wise)

ventral, dorsal

describe habitat and “mode of living” for class errantia

mostly marine, free-living

describe 2 “modes of living” for class sedentaria

tube-dwelling, free-living

organisms in class sedentaria generally have less _____ and ____ than errantia

parapodia, setae

“monoecious worms with a clitellum” describes which order?

clitellata

earthworm classification (phylum, class, order, genus)

phylum annelida, class sedentaria, order clitellata, genus lumbricus)

how do earthworms eat?

ingest soil, filter out food

path that food takes through earthworm digestive tract

mouth, pharynx, esophagus, crop, gizzard, intestine, anus

fleshy extension of first body segment that partially covers mouth opening

prostomium

what are the “hearts” of earthworms like?

aortic arches

aortic arches are connected to the ___ blood vessel

dorsal

the ventral blood vessel takes blood to the…

body

the dorsal blood vessel takes blood to the…

aortic arches

the ____ side of an earthworm is darker

dorsal

most organs are located in the ____ region of the earthworm

anterior

seminal vesicle description and function

larger, store sperm

seminal receptacle description and function

smaller, receive sperm

earthworms have 2 sets of ____ for sperm excretion and receiving

pores

leech classification (phylum, class, family)

phylum annelida, class sedentaria, family hirudinidae

leeches are ___parasites

ecto

leeches have these 2 suckers

anterior, posterior

anterior sucker primary function

feeding

posterior sucker function

attachment

is the clitellum closer to the earthworm’s anterior or posterior end?

anterior

leeches have ___ internal segmentation than other annelids

less

what is the only time the clitellum is present in leeches?

breeding season

crop function

stores soil

gizzard function

mechanical digestion